fix the value of nugget

Dear All,

I'm running Universal kriking method and I need to set the value of nugget
in the variogram model to zero even after fitting a variogram, I need the
fitted variogram to have a zero nugget. How can I do this please.

Showing what you've tried would help. Assuming you use package gstat,
you can pass a variogram model without nugget (e.g. vgm(1, "Exp", 300) )
to fit.variogram, and no (=zero) nugget will be fitted.

another question please, some times when I run my code I get this error
message (LDL factor) what this mean? and how can I solve it.

It means the covariance matrix is (too close to) singular; this happens
if you have (nearly) duplicate observations, or a variogram model that
gives rise to (nearly) perfectly correlated observations, such as the
Gaussian model.

Best Regards
Sherien

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Edzer Pebesma
Institute for Geoinformatics (ifgi),  University of M?nster,
Heisenbergstra?e 2, 48149 M?nster, Germany; +49 251 83 33081
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